The invention relates to a process for the reaction of styrene derivatives with ethylene in the presence of a nickel catalyst which carries a phosphorus-oxygen chelate ligand, styrene derivatives being obtained which are extended with ethylene at the olefinic double bond and in which a double bond remains in the extension chain formed.
Such styrene derivatives extended with ethylene are interesting intermediates which, owing to the double bond remaining in the extension chain, are suitable as precursors for graft polymers, for example with methyl methacrylate or maleic anhydride, or polymer-analogous reactions can be carried out using them. The styrene derivative employed according to the invention can moreover carry the substituents mentioned further below, which make possible other reactions or introduce other properties into a polymer. Of particular interest are products obtainable according to the invention in which the styrene derivative carries a further vinyl group, i.e. is, for example, divinylbenzene. In this case, mainly only one vinyl group is extended. The extended styrene derivatives formed in the course of this are bifunctional; they carry two olefinic double bonds of different reactivity. The unextended vinyl group can then be utilised in a manner known per se for styrene-analogous homo- or copolymerisations. The polymers produced therefrom furthermore carry their poly(oligo)ethylene side chains from the extension according to the invention bonded via the aromatic compounds and are thus poly(oligo)ethylene-modified. Graft reactions, derivatisations, cross-linkings and other reactions can then be carried out on the double bonds of these side chains.